Underwood, whom Brad Paisley had teased was prepared to deliver the night's most show-stopping moment, followed through on the promise, and her rendition of gospel classic "Softly and Tenderly" was spellbinding. At one point, as images of victims of the massacre manifested on a screen behind her, she got choked up, but eventually completed the song.

"Best performance I've ever watched on an awards show. Carrie Underwood on the CMAs," one viewer tweeted, while another noted "Carrie Underwood just delivered the performance of the night. What a beautiful way to honor so many lives lost."

A lone gunman killed more than 50 people at the Route 91 Harvest Festival in Las Vegas on October 1 and wounded dozens and dozens more while shooting down at crowds from an open window in his hotel room.

Underwood had previously bemoaned the tragedy on Twitter, noting on October 2: "Woke up to such horrible news. We are praying for the victims and their families. May the Lord bring some comfort to them."